Female sex hormones called oestrogens can worsenallergic reactions in women, says a study.”Women are more likely to suffer lethal allergicreactions because the female sex hormone makes thecondition worse,” says a Telegraph report, quoting thestudy by the National Institute of Allergy and InfectiousDiseases in the US.Researchers found that oestradiol – a type of oestrogen- enhances the levels and activity of the chemical whichdrives life threatening allergic reactions in women.One such condition is anaphylaxis – an allergicreaction triggered by food, medication or insect stingsand bites.In experiments on mice, the team found that femalemice experience more severe anaphylactic reactions thanmales.Oestrogen influences blood vessels, enhancing thelevels and activity of an enzyme that causes some of thesymptoms of anaphylaxis.The researchers found that giving oestrogen-blockingtreatments to female mice reduced the severity of theirallergic responses to a level similar to those seen inmales.